Known tape printing apparatus of the type with which the present invention is generally concerned are disclosed in EP-A-322918 and EP-A-322919 (Brother Kogyo Kabushiki Kaisha) and EP-A-267890 (Varitronics). The printers each include a printing device having a cassette receiving bay for receiving a cassette or tape holding case. In EP-A-0267890, the tape holding case houses an ink ribbon and a substrate tape, the latter comprising an upper image receiving layer secured to a backing layer by an adhesive. In EP-A-322918 and EP-A-322919, the tape holding case houses an ink ribbon, a transparent image receiving tape and a double-sided adhesive tape which is secured at one of its adhesive coated sides to the image tape after printing and which has a backing layer peelable from its other adhesive coated side. With both these apparatus, the image transfer medium, such as an ink ribbon, and the image receiving tape, such as a substrate, are in the same cassette.
There is a different type of tape printing apparatus which is described for example in EP-A-578372, the contents of which are herein incorporated by reference. In this printing apparatus, the substrate tape is similar to that described in EP-A-267890 but is housed in its own tape holding case while the ink ribbon is similarly housed in its own tape holding case.
In all of these apparatus, the image receiving tape passes in overlap with the ink ribbon to a print zone consisting of a fixed print head and a platen. The print head can be pressed against the platen to cause an image to transfer from the ink ribbon to the image receiving tape. There are many ways doing this, including dry lettering or dry film impression, but the most usual way at present is by thermal printing where the print head is heated and the heat causes ink from the ink ribbon to be transferred to the image receiving tape. Alternatively, the print head may be in direct contact with a thermally sensitive image receiving tape whereby when the print head is heated, an image is defined on the image receiving tape.
Tape printing apparatus or label printers are generally designed to be handheld or small desktop apparatus. Such apparatus are generally provided with an increasing number of different functions and options. However, the number of keys available for selecting these functions and options is limited by the compact nature of these products. At the present, individual functions, such as character size or font are selected by activation of a dedicated key. The number of functions available in this way can be increased by the use of shift keys. However, this can make the setting or selecting of the various functions complicated, particularly if there are a large number of functions or options to be selected. This can be a time consuming process. Additionally, it may be difficult for the user to clearly determine what options are available and indeed what values have been selected for a given option.